Re: [PATCH v2 1/1] pgo: Fix allocate_node() v2

Jarmo Tiitto
2021-06-04T09:41:47Z

Kees Cook wrote perjantaina 4. kesäkuuta 2021 0.36.39 EEST:
> On Thu, Jun 03, 2021 at 02:14:24PM -0700, Nathan Chancellor wrote:
> > On 6/3/2021 6:38 AM, Jarmo Tiitto wrote:
> > > Based on Kees and others feedback here is v2 patch
> > > that clarifies why the current checks in allocate_node()
> > > are flawed. I did fair amount of KGDB time on it.
> > >
> > > When clang instrumentation eventually calls allocate_node()
> > > the struct llvm_prf_data *p argument tells us from what section
> > > we should reserve the vnode: It either points into vmlinux's
> > > core __llvm_prf_data section or some loaded module's
> > > __llvm_prf_data section.
> > >
> > > But since we don't have access to corresponding
> > > __llvm_prf_vnds section(s) for any module, the function
> > > should return just NULL and ignore any profiling attempts
> > > from modules for now.
> > >
> > > Signed-off-by: Jarmo Tiitto <jarmo.tiitto@gmail.com>
> >
> > I agree with Nick on the comments about the commit message. A few more small
> > nits below, not sure they necessitate a v3, up to you. Thank you for the
> > patch!
>
> It would make my life easier to get a v3. :) I agree with all of
> Nathan's suggestions. :)
>
> Thanks!
>
> -Kees
>
> --
> Kees Cook
>
Hello,

Ok, I'll make the requested changes, noted by Nathan and post v3 patch soon. :-)
Btw. These patches were based on kees/for-next/clang/features branch.

Thanks for patience.
-Jarmo